A Specific Light Ion “dE-E-T” Telescope

A telescope was developed and tested. It is specific in its particle identification, and is used at the 7 MeV-300ps burst-width Van de Graaff accelerator. The telescope is made of two multi-wire-parallel-plate-avalanche-counters (MWPPAC), providing energy-loss and time, and a hexagonal pilot-U scintillator, viewed by two photomultipliers (PM), providing time and energy. By measuring the ratio of amplitudes on opposite sides of the scintillator, and by applying an on-line time- and pulse-height-correction procedure the time-resolution of the pilot-U scintillator reduces to 300 ps and the pulse-height resolution reduces from 35 to 28 %. Two-dimensional spectra of dE versus E, and E versus time-of- flight, are shown for 241Am and for samples of Ni and Ta, irradiated by 8.0 MeV neutrons. By selecting areas in these two-dimensional spectra one deduces particle energy spectra with outstanding foreground to background ratio and reasonable statistical accuracy in short acquisition times.